The street map of Boston's historic downtown reads like a dartboard, with the brick-paved void of City Hall Plaza as its bull's-eye. And City Hall itself, the imposing concrete building that dominates the plaza, has taken plenty of darts over the years. Unveiled in 1969 amid civic excitement and critical acclaim, it has been called one of the foremost examples of Modernist architecture—and the ugliest building in the world.

Architects and preservationists consider it an important building, possibly a great one, but even ardent defenders acknowledge that it is an acquired taste. Those who never acquired that taste—including hundreds of municipal employees—decry its imperious scale, unyielding surfaces, and cavernous and disorienting interior. Love it or hate it, it seems, no Bostonian remains neutral on this particular subject.

All of which was grist for the mill of city life until 2006, when Mayor Thomas M. Menino abruptly announced that he intended to sell the controversial landmark and build a new city hall on the South Boston waterfront. The old building, he said, was outdated and inefficient. In a booming commercial real estate market, he believed it would command a price sufficient to build a showcase replacement, and spur further development.

Once they'd caught their collective breath, preservationists and green building professionals joined forces in a determined effort not only to save the building but also to make it a showplace for green preservation. Now, the worldwide economic recession may have bought them the time they need to make their case.

Boston city Hall is the centerpiece of a 1960s urban renewal project that replaced 90 acres of a down-at-the-heels entertainment district known as Scollay Square. The winning entry in a high-profile national competition, the Brutalist building designed by Kallmann, McKinnell and Knowles was hailed upon completion as a glowing symbol of a resurgent "New Boston."

Unfortunately, the glow did not last. Brutalism's star would soon go into eclipse and City Hall's challenges become glaringly obvious. A massive structure surrounding an open atrium and perched on multistory concrete columns, the building casts deep, unwelcoming shadows. Its form—described by some residents as a doughnut on stilts—funnels winds that gust off Boston Harbor and swirl across the vast, often empty plaza. Read Dwight Young's column on Brutalism